This proposal is an interdisciplinary approach to a biochemical assessment, isolation, and characterization of immunobiologically active RNA molecules able to transfer tumor specific and/or non-tumor specific sensitivity to lymphoid cells. Our objectives are the following: 1) To isolate and fractionate RNA from lymphoid tissues of syngeneic strain-2 guinea pigs immunized against line-1 or line-10 tumors; or other non-tumor antigens, KLH or ARSNAT. 2) Each RNA fraction will be assessed for its ability to tranfer tumor or other antigenic specific sensitivities to guinea pig peritoneal exudate cells in vitro; utilizing the agarose droplet cell-migration-inhibition correlate of delayed type hypersensitivity and the thymidine incorporation assay. 3) Fractions of RNA capable of converting lymphoid cells will be purified by Oligo-dT-cellulose chromatography and polyacrylamide gel electrophoresis. 4) The RNA fraction which is biologically active will be used as templates for reverse transcriptase. The cDNA product will be cloned in plasmid pBR322. RNA from clones containing hybrid plasmid DNA will be tested for biological activity. 5) DNA from the active clones will be further characterized biochemically. 6) Fractions of RNA capable of converting lymphoid cells will be further characterized as to their homogeneity and/or heterogeneity of the biologically active RNA species and the number of RNA molecular species found in the active extracts. 7) To assess the molecular weight and class of RNA to which the active species belongs. 8) Biologically active RNA species will be assessed for the presence of "capped" structures in the poly-A containing Fraction II, possessing immunobiological activity. 9) The base composition and sequence of the biologically active RNA fraction(s) will be determined. 10) To assess at each step of the purification stages, the biological activity of the isolated RNA molecules. 11) To compare the nucleotide sequences of active RNA species between different lymphoid tissues of the same animal; and from different animals immunized against tumor or chemically defined antigens.